Hydrogen peroxide reacts with potassium permanganate to generate bursts of oxygen that make a burning ethanol mixture crack, pop, and roar like cannon fire; adding a metal salt can color the flame.

1. Place a heat mat on the bench and set up a tripod and safety screen facing the audience.
2. In a large porcelain evaporating basin, measure about 30 mL of 20 volume (6%) hydrogen peroxide.
3. Add about 20 mL of ethanol to the same basin and swirl gently to mix.
4. Stir in a small spatula measure of a flame-coloring salt (for example, lithium chloride for red).
5. Move the basin onto the tripod where it is stable and clearly visible behind the safety screen.
6. Ignite the mixture at arm’s length using a tapered spill or extended lighter.
7. Using a spatula, sprinkle small portions of solid potassium permanganate onto the burning liquid over time; pause between additions to let each portion react.
8. Continue adding tiny amounts until a series of sharp cracks and bangs is produced; do not add too quickly.
9. Extinguish any residual flame safely and allow the apparatus to cool before disposal and cleanup.

Cannon Fire - Any Excuse for a Chemistry Experiment:

📄 Full procedure and risk assessment - SSERC: https://www.sserc.org.uk/resources/chemistry-resources/chemistry-resource-list/cannon-fire/

• Try different metal salts to compare flame colors (e.g., sodium chloride for yellow, copper(ii) chloride for green-blue), ensuring the salt is dry and used sparingly.
• Dim the room lights so the flame color is more visible, keeping the safety screen in place.

• Safety glasses or goggles required; wear a lab coat and heat-resistant gloves.
• Use a safety screen between the apparatus and observers at all times.
• Hydrogen peroxide (20-volume) is corrosive/harmful; avoid skin and eye contact and clean spills immediately.
• Ethanol is highly flammable; keep sources of ignition away and cap bottles promptly.
• Add potassium permanganate only in tiny portions; never dump in all at once to avoid violent spattering or ejection of burning liquid.
• Perform on a heat mat with a stable tripod; keep combustible materials clear of the setup.
• Handle hot ceramics with tongs and allow full cooling before touching or moving.
• Ensure good ventilation; have a fire blanket and suitable extinguisher nearby.
• Dispose of cooled residues according to local guidance for oxidizers and flammable waste.

• What evidence shows a chemical reaction is occurring? (light, heat, sound, gas evolution, and color changes)
• Identify the oxidizers and reducer in the reaction. (hydrogen peroxide and potassium permanganate are the oxidizers, ethanol is the reducer)
• How does adding a salt change the flame appearance? (metal ions emit characteristic colors when excited in the flame; e.g., Li+ gives red)